Sector Format - HP 7925D Service Manual

Part I Page
THEORY OF OPERATION
Introduction A-I
Addressing Structure A-I
Addressing Modes A-I
Surface Mode " A-I
Cylinder Mode A-3
Sector Format A-3
Functional Description A-4
Controller A-4
Microprocessor Module A-9
Eight-Bit Microprocessqr A-9
Read-Only Memory (ROM) A-9
Operation Control Registers A-9
HP-IB Interface Module A-IO
Data Path Module
~
. A-IO
FIFO and Data Serializer/
Deserializer A-IO
Data Formatter
0 ' •
A-IO
Data Separator A-IO
CRC Generator/Checker '" A-10
DMA Machine A-IO
Operation Control System A-IO
Drive Identification A-IO
Drive Operation Control A-IO
Access Not Ready A-II
Drive Not Ready A-ll
Seek Check A-II
First Status A-II
Drive Fault A-II
Format '" '" A-12
Read Only A-12
Attention A-12
Attention Logic A-12
Spindle Rotation System A-12
Spindle Logic Initialization A-12
Door Control Logic A-12
Run Spindle Command Logic '" A-12
Phase Encoding and Decoding A-13
Speed Control A-13
Motor Current Regulation A-14
Dynamic Braking A-15
Speed Down Detection A-15
Overcurrent Protection A-15
Overvoltage Protection A-15
Head Positioning System A-15
Initial Head Load Operation A-16
Normal Head Unload Operation A-17
Seek Operation A-18
Offset Operation A-21
Recalibrate Operation A-22
Emergency Retract Operation A-23
Sector Sensing System A-23
ReadlWrite System A-24
Head Selection A-24
Read Mode Operation A-25
Write Mode Operation A-25
ReadlWrite Fault Detection A-26
Fault Detection System A-26
Illegal Address Detection A-26
CONTENTS
I
Timeout Fault Detection " A-27
AGC Fault Detection A-27
Carriage Back 'Fault Detection A-27
Interlock Fault Detection A-27
ReadlWrite Fault Detection A-28
Non-destructive Write Faults A-28
Destructive Write Faults A-29
Air Circulation and
Filtration System A-29
Power Distribution System A-30
Power Panel Assembly A-3I
Power Supply Assembly A-3I
Voltage. Regulator Circuits A-3I
Voltage Protection Circuits A-32
Supply Voltage Distribution A-32
Part II Page
MAINTENANCE
Special Test Equipment _ A-33
Preventive Maintenance A-33
Part III Page
ALIGNMENT AND ADJUSTMENT
Installing the DSU A-35
On-Line Checkout
~
A-35
Part IV Page
TROUBLESHOOTING
Diagnostic Test Programs A-37
Self Test A-37
Modes of Operation A-37
Operating Mode A-38
Service Mode A-38
Self-Test Example A-38
Troubleshooting Flowcharts A-38
Power Sources A-38
Visual Indication of Drive Status A-39
Disc Service Unit A-39
System Functional Diagrams A-39
Wiring Connections A-39
Power Distribution A-39
Part V Page
REMOVAL AND REPLACEMENT
Card Cage PCA's A-75
Self-Test PCA-AI3 A-75
Card Cage Fan A-76
Part VI Page
REPLACEABLE PARTS
Introduction A-77
Part VII Page
RECORDING FORMAT AND
COMMUNICATION PROTOCOL
Introduction A-81
Recording Format A-8I
Channel Communications A-82
Idle States A-84
Controller Secondaries ' A-84
A-iii